On 27 May 2011, at 08:35, Emil Axelsson wrote:

Hello!

Lacking a proper blog, I've written some notes about Data.Unique here:

http://community.haskell.org/~emax/darcs/MoreUnique/

This describes a real problem that makes Data.Unique unsuitable for implementing observable sharing.

Looking at the source for Data.Unique shows that its implemented as an Integer, starting at 0,

when the IO monad is started - so the values are only unique within a single I/O run,

and are definitely not comparable across runs...

The document also proposes a solution that uses time stamps to generate symbols that are "more unique".

Does anyone have any comments on the proposed solution? Are there any alternatives available?

I haven't had time to look at that part yet ....

Thanks!

/ Emil

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